Kinetics and mechanism of the interaction between human serum albumin and monomeric haemin

Abstract

The interaction of human serum albumin with monomeric haemin has been investigated by detailed kinetic analysis in dimethyl sulphoxide/water (3:5, v/v). The results obtained under conditions of albumin saturation of haemin and under pseudo-single turnover conditions indicate that methaemalbumin is formed in a two-stage, single-intermediate process. The initial association between the haemin and human serum albumin is a chemically controlled process (k1 = 1.7 X 10(5) mol-1 . s-1 . dm3 at 24 degrees C); the variation of K1 with pH exhibited a well defined pK of 5.9. The overall equilibrium constant, calculated by using microscopic rate constants, is 1.1 (+/- 0.5) X 10(8) mol-1 at 24 degrees C. The data and conclusions are consistent with a general binding mechanism for albumin in which intermediate formation is followed by an entropy-controlled internalization of the ligand.

Human serum albumin: From bench to bedside

“…Values of k on , k off , and K d (=k off /k on ) are 7.4 Â 10 5 M À1 s À1 , 9.6 Â 10 À3 s À1 , and 1.2 Â 10 À8 M, respectively, under para-physiological conditions (Adams and Berman, 1980;Peters, 1996;Bocedi et al, 2005). Remarkably, heme-Fe(III) binding to HSA is modulated allosterically and inhibited competitively (see Section 7.3) (Bocedi et al, 2005;Ascenzi and Fasano, 2010).…”

Interaction of Bovine Serum Albumin and Metallothionein

“…7) Perhaps, the most outstanding property of albumin is its ability to bind reversibly an incredible variety of ligands. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Albumin has a high affinity for fatty acids, hematin, bilirubin and a broad affinity for small negatively charged aromatic compounds. It forms covalent adducts with pyridoxal phosphate, cysteine, glutathione, and various metals such as Cu(II), Ni(II), Hg(II), Ag(I), and Au(I).…”

Interaction of cinnamic acid derivatives with serum albumins: A fluorescence spectroscopic study

“…Serum albumins are the major soluble protein constituents of the circulatory system contributing significantly in the physiological functions as carrier proteins [10][11][12]. The most widely studied serum albumins, probably because of their well characterized structures and known functions, are either obtained from bovine (BSA) or human (HSA) sources.…”